def find_lost_num(array=[]):
    result = [0, 0]
    xor_result = 0
    for i in range(len(array)):
        xor_result ^= array[i]

    if xor_result == 0:
        raise ValueError
    separator = 1
    while 0 == (xor_result & separator):
        separator <<= 1
    for i in range(len(array)):
        if 0 == (array[i] & separator):
            result[0] ^= array[i]
        else:
            result[1] ^= array[i]
    return result


my_array = list([2, 3, 4, 5, 4, 2])
print(find_lost_num(my_array))
